Telephone-exchange system.



J. vL. WRIGHT', TELEPHONE EXGHNGESYSTBM. v

APPLICATION FILED JAN. 3, 1997.' v

' Patented May 21,1912.-

2 SHEETS-SHEET 2.

the contacts* will vin turn keep the solenoid,

toits normal position after the f i'ontactsi1 and vsnre'mainf broken -for quite a while zas,- would 'bev the case "when-a subscriber hangs up Vhis telephone. atth'e end'ofV a conversation'.

and rapidmakes and-breaks between it and A active allowing ythe core a? to remain ydrawn Vup soI longas impulses are being transmitted. Between every set of impulses there is a long make or pause. causedby the subscriber setting up sending device` for transmitting another vset of impulses. f Durvgized` Y Imal posit-ion.'v At'the end of the conversa'- ing this linterval'thesolenoid A is denerand vits core a5 drops downto its nortion 'the relay S becoi'ning4 denergized closes the 'contacts s. and-s4 causing the solenoidA A to become active 'but at the same time the circuitof the solenoid B is broken at the contacts s ands andthe core b5 thereupon drops, opening the springs b and Z2 disconnecting battery from the contact s2 and dep energizing the solenoid A whose core-,a5 thereupon drops. 'It will be seen 'from the foregoing descri tionof these two solenoids that the. core o the solenoid A drops between-every group or setl of impulsesfand that the core of the solenoidB only drops at the end of a conversation. With this combinat'ion I am enabled to use the solenoid'A switches.

leasing various switches. When the core of' for sending a rotary or switching impulse after each set of signals so as to work thev side switchesin the selector and connector The solenoid. B is used for rethis solenoid drops down battery is laced simultaneously on the wires 4 and 5 y the closure of the springs b2, o and b4. Battery is ,afterward disconnected .from the wires 4 and 5 by. the core a5 of the solenoid A drop lingand opening the contacts aa and a4. Bridged battery is connected between the windings of the relay S and retardation coil I for supplying talking battery to the calling subscriber.V The condensers CE and C are inserted in the wires 3-4 and 24-5 'respectively to prevent battery iiowing to the various switches.

VVhenthe core of the solenoid A drops down between each group .of impulses in ad# dition to connecting battery momentarily to number 5 side of the trunk it also connectsv While this solenoid vis activenbatter isconnected to the contact s2 of the relay ibamos g is, iaoetoiteith and Erickson. i-Wiii not.

'attempt'jto describe these circuits in detail. The first. selector switch G consists of `the vertical vrelay vV which when energized closes the/circuit of the vertical magnet X'which inturn causes the spindle. Z carrying the lwipers'to step upvertically. The rotary re-v -la V whenenergized operates the private reA ay U causing the s ide switches to malte one step.' The rotary magnet X has its cir'- cuitclosed after the side switches have made Vone-movement and -will'continue to vibrate causing the spindle Z to rotate until the test wiper' e nds a'contact free from ground.. As soon as this happens the side switches make still another movement disconnecting the vertical and rotary relays from'the trunk wires and close the trunk wires themselves The last through to the trunk wipers. movement of the sidel switchesl also connects thetrunk release relay J"`to the test wiper e. The magnet J is the release magnet and when operated restores the switch to its normal position. The circuits of the second selector switch Gfare similar to those fao of the first selector switch and need not be described. Referrin now to the connector switchG2, the circuits shown are the same as in the Letters' Patent before referred to,

with the exception of the release mechanism.l

In the present case a lrelease relay J4 is used,

the release magnet J5.- Instead "of testing on a thirdor test wiper I do the testinfT directly on the rotary or sleeve side of the line. In place of the ordinary back release relays which are connected t'o the trunk wires 14 and 15 respectively, I have replaced themvwith the retardation coils-I2 and I3 with bridged batteryJbetween them for 'supwhich when actuated closes the circuit .of l.

plying current to the called subscriber. In

this particular case I have shown the contacts in the connector'switch connected di' rectlyto the calling line as I wish to illus trate and show the method of calling back on your own line. The changes I have made in this circuit do not aieet the operation of this switch in the slightest. relay V, rotary relay V, private relay U2 and theringin relay Y, remain unchanged and the metho of releasing is; the same.

The vertical The operation of this system is as foli loWs:-Referring to Fig. 1, the subscriber at station A desiring to be connected with station A on the same line ist removes his telephone which closes the line circuit, energizes the relay S which in turn closes the circuit of the solenoid B. The core of the solenoid B now b-ing drawn up battery is connected to the contact s2 of the relay S by the following ath: battery B, 22, S0, b', 23, s2. The relay keeps the circuit of the solenoid 'A open. Theisubscriber at station A after removing his telephone sets upihis sending device to at this time being e1 icrgi Zed selector switch, while battery being on line wire number 8 disables the busy test the desired number` and this in running'down makes and breaks the contacts 0 and 0 according'to the number of impulses to be sent. These makes and breaks operate the relay S at the centralv oiiice which in turn makes and breaks its own contacts. The making andbreaking of the'contacts s2 and s* cause the solenoid A .to become energized and draw up the core a5.' The making and breaking of the contacts .s and s keep the solenoid B energized, while the making and breaking of the contacts s2 and s3 send impulses over the trunk Wire number 4 to the first selector switch. These impulses of course,.correspondto the makes and breaks of the contacts o and 0. 4After this first sety of impulses there is a momentary closure of the line due to the subscriber setting his sending device for another set of impulses. During this time the relay S remains energized and the core 0,5 of the solenoid A drops down and in doing so momentarily closes together the contact springs a, "a" and a2. This closure places battery on the trunk wire 5 and on the line wire 3. Battery be* ing thus momentarily placed on the trunk wire 5 operates'the rotaryrelay in the first placed relay inthe connector switch as will be described later.

` lay V which to Fig. 2, the first set of over number ,Ll side of the trunk operates the relay V which in turn closes the circuit of the magnet X which causes the spindle Z to step up vertically Referring nowl and bring the wipers opposite a row of contacts leading to the proper group of s'econd' selector switches. After the first set of impulsesA the solenoid A becomes deenergized and its core dropping down places battery on number 5 side of the trunk by the following path: battery B, 22, s, s-, 28, a2, a. 27, 5. This impulse operates the rein turn closes the circuit of the private relay U causing the side switch to make one movement cutting on the rotary magnet X- which causes the spindle to ro` l' tat-e 'untilthe test wiper finds the Contact leading to an idle second selector switch.

Whensuch a switchv is found the side switch makes one more movement cutting olf the vertical and'rotary relays and connects the "trunk wires 4 and 5 to the trunk wipers whichv rest upon contacts' leading to the second selector switch. The subscriber now being connected t0 theV second selector switch `sends in the second set of impulses which now operate the second selector switch Gr in the same manner that the 'first set 'of impulses operated the first vselector switch. The subscriber now-being connect? ed to a connector switch containing multiples of the desired line sends in the third down.

set of impulses.."1`his set of impulses coming in operates the relay V4 which in turn closes the circuit of the magnet X4 which in turn causes the spindle Z2 to step up vertically and bring the wipers opposite a vrow containing the contacts leading to the desired line. The rotary impulse now coming in operates the relay V5 causing the side switch to make one movement, disconnecting the magnet X4 and in its place connecting the magnet X5, itv also connects the test relay J4 to the sleeve side ef the line througlrthe normally open'contacts a and u of the relay Ux The fourth set. of iin-I pulses now coming in operate the relay V4 which now closes. the circuitofl the magnet X5 which in turn causes the spindle to rotate and bring the wipers to rest uponv contacts leading to the desired line. In this case, the desired line happensto be your own line as the party wanted is connected to the same pair of line wires. The last rotary impulse now eoming in closes the circuit of the relay V5`wliich in turn closes the 'circuit of the relay U2 connecting the test relay J* to the sleeve or number 19 sidev of the trunk.- At the same time that this relay is connected to the sleeve sideof the trunk, battery is placed on the tip side of line. and as the tip-'side of the line in this case is connected to the sleeve side of Vthe trunk it is impossible for `the test relay to operate as itis connected to battery itself. The above condition can only be brought about when tryingto signal back on thev line whichinitiates the call. If calling for another line' and that line happens tobe busy, ground `would be connected to the tip side of the trunk through the battery supply 'relay and that line would testbusy and the relay J4 would become energized and close the circuit of the magnet- J5 restoring the switch to its normal position. The subscriber nowbeing connected to his own line sets up his sending device so as to send in a set of ringing impulses. Thesel impulses now coming in operate the relay'V* which in turn closes the circuit of the rlnging rey layY whichbecame connected when the,

last rotary .or test impulse was sent in, y

causing thefside switch to make one more;

movement. IThese ringing impulses operating the relay Y place generator current-l on the called line ringing the bell ofthe desired parts who upon removing his telephone is ena led to talk with the party on thesameline.4 ylg At the end of the conversationthecallingsubscriber upon hanging uphis telephone effects the release of the various vswitche'sin the following manner: During conversation the core of the solenoid B 'remainssdrawn -"up while that of the'3 solenoid A remainsl When the calling subscriber hangs y hone the relay S becomes deup his tele. A

'ereupon the solenoid A atl once energized w draws up its core a while the core of the solenoid B begins to drop and as soon as it assumes itsl normal position battery. is connected to both sides of the trunk by the following path: battery B, at, as, bt, b3, b2, 21,31. After it has assumed its normal position the contacts Z) and b are broken, 'opening circuit of the solenoid A whosee corea5 thereupon begins- .to drop and as soon as it assumes its normal position the contacts ckand at lare broken and batteryl The circuit'of the relayiJ2 in the secondselector switchd was closed in series' with that of J4 and upon operating closes the circuit of theA magnet J 3 restoring the second `selector switch toits normal position. In the rstv'selectorswitch the relay J has its circuit closed in series-.with the magnet J 3 'and becomingenergized closes the circuit ofthe magnet J restoring the Vfirst selector switch to its normal' position. All4 thel apparatus is now returned to its normal or starting position and ready to be used for another call. y

Having thus described my invention what I claim and desire to secure by Letters Patent is:

l. In a telephone exchange system a` plurality of subscribers lines and automatic Vswitching apparatus for interconnecting them,v means in the switching apparatus for testing a subscribers line, and other means simul-tai'ieously oper'atedto producea balance of potential'son the first means in case the linetested is alsothe line calling, but

no't. otherwise, substantially as described.

2. In a telephone exchange Vsystem a plu i rality of subscribers. lines and automatic switches `for interconnecting them, an elec 'tromagnet' brought into use when completing aoonnection, for the purpose of testing the' line wanted to ascertain if it is busy,

-meansto produce a. difference in potential between the testing terminal of each line and the testing terminal of said' magnet when :ence of potential incasethe line calling is i the line becomes=busy,-and means associatedv withthe switches'for balancing said differtest relay-is energized, whereby a balance of potentials is produced across the terminals of said relay when the line calling is also the line called, substantially as described'. I

4L In atelephone exchange system a plurality of subscribers lines and automatic switches for interconnecting them, answer ing and calling multiple terminal connections for each line, means for initiating a connection through the answering terminal connections and one or more automatic switches to the calling terminal of the line wanted, means for grounding a lline terminal whenl the line becomes busy, a test relay associated with a connector switch and connected from a test terminal to battery, and 4means vfor simultaneously applying said relay to the calling terminal of the wanted line and at the sametime connecting battery to the corresponding answering terminal of the calling `line, whereby a balance of potentials is produced on thel relay `it the calling and called lines are the same, substantially as described.

5. Apparatus for testing telephone or signaling terminals comprising (l) means adapted when a terminal is idle to maintain a predetermined potential thereon; (2)

means becoming active when the line of the terminal is calling or called, to change the potential thereon; (3) means acting when the line is both calling and called to neutralize or balance the change in potential; and (4) means adapted to be broughtinto conjunction with a line terminal for testing purposes, said means being responsive to the changed potential when the line is calling or called, but remaining irresponsive when the lineisboth calling and'called.

Intestimony whereofl aiflx my signature p in presence of two witnesses.

Jos'ErHL. wRrGHT.-

Witnessesi JAMy s H. Mann,

E. y DMoNsToN, Jr.

Contes of this patent 'may -he'obtainvdforvve cents each, by addressing the Commissioner o! atents.

=` i i 2 yf;NATashizigton,.K1D.C. 

